North Shore Entertainment...
Chupu Charters will take you out ocean fishing, 808-637-3474. Country Cycles will rent you a bike, 808-637-9991; Deep Ecology will take you out diving, 808-637-7946. Or maybe you would like to have a Shark Encounter, 808-351-9373. Sunset Suzy will give you private surf lessons, 808-781-2692. So will Doug Deal, 808-351-5392.

Some of the best snorkeling can be done right here at Kuilima Cove,the public beach to the right of the hotel. Shark's Cove is even better, especially if you're brave enough to do some underwater cave exploring. North Shore Catamaran in Haleiwa does 4-hour snorkel trips in a sailing cat from June to September, and the charge is $74 a person. 808-638-8279. 

Spend a day walking at the Waimea Falls Park to see waterfalls and Hawaiian flora. After you wear yourself out with all these things, maybe a restful and educational day at the Polynesian Cultural Center will suit you.

You will find so many things to do, it will be difficult to decide on which to do first.